An extracellular congenital nephrogenic diabetes insipidus mutation of the vasopressin receptor reduces cell surface expression, affinity for ligand, and coupling to the Gs/adenylyl cyclase system

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Item Type:	Article
Title:	An extracellular congenital nephrogenic diabetes insipidus mutation of the vasopressin receptor reduces cell surface expression, affinity for ligand, and coupling to the Gs/adenylyl cyclase system
Creators Name:	Birnbaumer, M., Gilbert, S. and Rosenthal, W.
Abstract:	The mutation of the type-2 vasopressin receptor (V2R) apparently responsible for X-linked congenital nephrogenic diabetes insipidus (CNDI) in the Q3 family consists of a T to C transition in codon 113, causing the change of Arg-113 to Trp. Arg-113 is located in the putative first extracellular loop of the V2R next to a frequently conserved Cys thought to interact via a disulfide bridge with a Cys of the second extracellular loop. The present study explored whether this mutation may account for the CNDI phenotype. The mutation was excised from the genomic DNA of a Q3 patient and introduced into the V2R cDNA, which was then placed into an expression plasmid and transfected into COS cells for transient expression and murine L cells for stable expression. Studies with L cells expressing similar levels of wild type and Q3 receptors showed that the mutant receptor has a 20-fold reduced affinity for arginine vasopressin (AVP) and stimulates adenylyl cyclase with an EC50 that is increased by a factor of about 60-fold. The same shift in the EC50 for adenylyl cyclase stimulation was obtained when deamino[8-D-Arg]vasopressin was substituted for AVP. Studies with COS cells revealed that at equal levels of transfected DNA, the mutant receptor is expressed at lower levels (about 20%) than the wild type receptor, indicating that the mutation hinders the transport of the receptor to the cell membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
Keywords:	Adenylate Cyclase, Amino Acid Sequence, Arginine Vasopressin, Base Sequence, Cell Line, Cell Membrane, Deamino Arginine Vasopressin, Nephrogenic Diabetes Insipidus, GTP-Binding Proteins, L Cells (Cell Line), Molecular Sequence Data, Point Mutation, Protein Binding, Protein Conformation, Post-Translational Protein Processing, Vasopressin Receptors, Recombinant Fusion Proteins, Signal Transduction, Animals, Mice, Cercopithecus Aethiops
Source:	Molecular Endocrinology
ISSN:	0888-8809
Publisher:	Endocrine Society
Volume:	8
Number:	7
Page Range:	886-894
Date:	July 1994
Official Publication:	http://mend.endojournals.org/cgi/content/abstract/8/7/886
PubMed:	View item in PubMed

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